True or False: Just like protons, the

Cell and chromosome characteristics?

rusak2 [61]

Answer:

hope the inserted image will help :)

Explanation:

5 0

3 years ago

Read 2 more answers

How would a collapsing universe affect light emitted from clusters and superclusters? A. Light would acquire a blueshift. B. Lig

Lady_Fox [76]

Answer:

Choice A: Light would acquire a blueshift.

Explanation:

When a universe collapses, clusters of stars start to move towards each other. There are two ways to explain why light from these stars will acquire a blueshift.

Stars move toward each other; Frequency increases due to Doppler's Effect.

The time period $t$ of a beam of light is the same as the time between two consecutive peaks. If $\lambda$ is the wavelength of the beam, and both the source and observer are static, the time period $T$ will be the same as the time it takes for light travel the distance of one $\lambda$ (at the speed of light in vacuum, $c$ ).

$\displaystyle t = \frac{\lambda}{c}$ .

Frequency $f$ is the reciprocal of time period. Therefore

$\displaystyle f = \frac{1}{t} = \frac{c}{\lambda}$ .

Light travels in vacuum at a constant speed. However, in a collapsing universe, the star that emit the light keeps moving towards the observer. Let the distance between the star and the observer be $d$ when the star sent the first peak.

Distance from the star when the first peak is sent: $d$ .
Time taken for the first peak to arrive: $\displaystyle t_1 =\frac{d}{c}$ .

The star will emit its second peak after a time of. Meanwhile, the distance between the star and the observer keeps decreasing. Let $v$ be the speed at which the star approaches the observer. The star will travel a distance of $v\cdot t$ before sending the second peak.

Distance from the star when the second peak is sent: $d - v\cdot t$ .
Time taken for the second peak to arrive: $\displaystyle t_2 =t + \frac{d - v\cdot t}{c}$ .

The period of the light is $t$ when emitted from the star. However, the period will appear to be shorter than $t$ for the observer. The time period will appear to be:

$\begin{aligned}\displaystyle t' &= t_2 - t_1\\ &= t + \frac{d - v\cdot t}{c} - \frac{d}{c}\\&= t + (\frac{d}{c} - \frac{v\cdot t}{c}) -\frac{d}{c}\\&= t - \frac{v\cdot t}{c} \end{aligned}$ .

The apparent time period $t'$ is smaller than the initial time period, $t$ . Again, the frequency of a beam of light is inversely proportional to its period. A smaller time period means a higher frequency. Colors at the high-frequency end of the visible spectrum are blue and violet. The color of the beam of light will shift towards the blue end of the spectrum when observed than when emitted. In other words, a collapsing universe will cause a blueshift on light from distant stars.

The Space Fabric Shrinks; Wavelength decreases as the space is compressed.

When the universe collapses, one possibility is that clusters of stars move towards each other. Alternatively, the space fabric might shrink, which will also bring the clusters toward each other.

It takes time for light from a distant cluster to reach an observer on the ground. The space fabric keeps shrinking while the beam of light makes its way through the space. The wavelength of the beam will shrink at the same rate. The wavelength of the beam of light will be shorter by the time the beam arrives at its destination.

Colors at the short-wavelength end of the visible spectrum are blue and violet. Again, the color of the light will shift towards the blue end of the spectrum. The conclusion will be the same: a collapsing universe will cause a blueshift on light from distant stars.

8 0

3 years ago

Which of these is an isoelectronic series? 1) na+, k+, rb+, cs+ 2) k+, ca2+, or, s2– 3) na+, mg2+, s2–, cl– 4) li, be, b, c 5) n

ss7ja [257]

An isoelectronic series is where all of the ions listed have the same number of electrons in their atoms. When an atom has net charge of zero or neutral, it has equal number of protons and electrons. Hence, it means that the atomic number = no. of protons = no. of electrons. If these atoms become ions, they gain a net charge of + or -. Positive ions are cations. This means that they readily GIVE UP electrons, whereas negative ions (anions) readily ACCEPT electrons. So, to know which of these are isoelectronic, let's establish first the number of electron in a neutral atom from the periodic table:

Na=11; K=19; Rb=37; Cs = 55; Ca=20; S=16; Mg=12; Li=3; Be=4; B=5; C=6

A. Na⁺: 11-1 = 10 electrons
K⁺: 19 - 1 = 18 electrons
Rb⁺: 37-1 = 36 electrons

B. K⁺: 19 - 1 = 18 electrons
Ca²⁺: 20 - 2 = 18 electrons
S²⁻: 16 +2 = 18 electrons

C. Na⁺: 11-1 = 10 electrons
Mg²⁺: 12 - 2 = 10 electrons
S²⁻: 16 +2 = 18 electrons

D. Li=3 electrons
Be=4 electrons
B=5 electrons
C=6 electrons

The answer is letter B.

7 0

3 years ago

A chemistry student needs 60.0 g of tetrahydrofuran for an experiment. By consulting the CRC Handbook of Chemistry and Physics,

Evgen [1.6K]

Answer:

67.492cm^3

Explanation:

To get the volume of tetrahydrofuran needed, what the student need to do is to apply mathematical calculations.

We know quite well that to obtain the volume of a substance, given the mass of the substance and the density of the substance is possible.

The volume of the substance is simply the mass of the substance divided by the density of the substance.

This is thus volume = mass/density

The mass given is the question is 60g while the density given is 0.889g/cm^3

The volume = 60/0.889 = 67.492cm^3

8 0

3 years ago

(a)-Use Lewis symbol store present there action that occurs between Ca and F atoms. (b)-What is the chemical formula of the most

Charra [1.4K]

Answer:

(a) The Lewis structure is shown in the image below.

(b) $CaF_2$

(c) Calcium loses 2 electrons to 2 atoms of fluorine and these 2 atoms of fluorine accepts each electron to form ionic bond.

(d) Calcium atom loses electrons.

Explanation:

Calcium is the element of second group and forth period. The electronic configuration of Calcium is - 2, 8, 8, 2 or $1s^22s^22p^63s^23p^64s^2$

There are 2 valence electrons of Calcium.

Fluorine is the element of group 17 and second period. The electronic configuration of the element fluorine is - 2, 7 or $1s^22s^22p^5$

There is 1 valence electron of fluorine.

The Lewis structure is drawn in such a way that the octet of each atom is complete.

Thus, calcium loses 2 electrons to 2 atoms of fluorine and these 2 atoms of fluorine accepts each electron to form ionic bond. This is done in order that the octet of the atoms are complete and they become stable.

Thus, the formula of calcium chloride is $CaF_2$ .

(a) The Lewis structure is shown in the image below.

(b) $CaF_2$

(c) Calcium loses 2 electrons to 2 atoms of fluorine and these 2 atoms of fluorine accepts each electron to form ionic bond.

(d) Calcium atom loses electrons.

5 0

3 years ago